1. Field of the Invention
This invention relates to a catalyst and process for hydrofining petroleum waxes. More particularly, this invention relates to a catalyst and process for hydrofining petroleum waxes using a catalyst comprising a metal hydrogenation component supported on a porous carrier containing alkali metal compound wherein the carrier possesses a novel pore distribution. Still more particularly, this invention relates to a process and catalyst for improving the thermal, light and UV stability of petroleum waxes by contacting the wax with hydrogen in the presence of a catalyst comprising at least one metal hydrogenating component on a porous alumina/silica carrier containing minor amounts of alkali metal and having a novel pore structure defined by the volume of pores having a diameter in the range of 60 to 150 A being greater than 80% of the volume of pores having a diameter in the range of 0 to 150 A and the volume of pores having a diameter in the range of 0 to 600 A being in the range of about 0.45 to 0.60 ml/g.
2. Description of the Prior Art
Naturally occurring petroleum waxes must be refined in order to provide high quality waxes of improved thermal, light and ultra-violet stability. Although treating raw wax with sulfuric acid or contacting it with absorbent clay has been used for improving the color, storage stability and oxidation resistance, it is now preferred to hydrorefine or hydrofine the wax in order to improve these properties, particularly when the wax is to be used for foods and drugs which requires a very highly refined wax in order to satisfy the requirements of the U.S. Food and Drug Administration (FDA). Hydrofining improves the properties of the wax by removing therefrom a very small amount of polar substances and other impurities and by hydrogenation or ring scission of polycyclic aromatic molecules. In order to produce a highly refined, high quality wax it is necessary for the hydrofining catalyst to have a sufficient amount of activity to be technically practical.